Combined insecticide and germicide



Patented Sept. 26,

INSECTIE v Edward R. McGowan, Hyattsvilie, and Lyle D. Goodhue, BeHeights, Md, asslgnors to Claude R. Wickard, as Secretary oi Agricultureof the United States of America, and his successors in omce No Drawing.Application April 14, 1943, Serial No. 483,000

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3'700. G. 757) 2 Claims.

This application is made under the act of March 3, 1883, as amended bythe act of April 30, 1928, and the invention herein described, ifpatented, may be manufactured and used by or for the Government of theUnited States of America for governmental purposes without the paymentto us of any royalty thereon.

This invention relates to a composition containing an insecticide and agermicide which will be dispersed in aerosol form when the compositionis released from a suitable dispenser, and has among its objects: theprovision of a combined insecticidal and germicidal aerosol; one whichis non-toxic to animals and, therefore, can be safely used in suchplaces as hospitals, public conveyances, dwellings, and dairy barnswithout the need for evacuation of the occupants; the provision of anaerosol of the above nature which is also non-combustible, to remove therisk of fire during use; and such other objects as will be apparent fromthe following description and appended claims. The subject-matter isrelated to that disclosed in the copending application of Goodhue etal., Serial No. 404,520, filed July 29, 1941, and granted June 8, 1943,Patent No. 2,321,023.

The invention comprises, in general, a combination of a suitableinsecticide and germicide as the active ingredients, dissolved in aliquiddispersing agent, which is non-toxic to man or animal, and whichmay be sprayed or released from a suitable container to cause dispersionof the active ingredients in aerosol form. If the particular dispersingagent used is not a solvent for both the insecticide and germicideselected, a mutual solvent which is also soluble in the dispersing agentis added. In some instances additionof an oil, which acts as a carrieror conditioner for the insecticide, is desirable.

The dispersing agent is of such nature that it is gaseous at normaltemperatures and pressures but can be easily maintained in a pressurecontainer and, when released as a spray in the air, the dropletsevaporate violently, thus shattering them. The other ingredients of thecomposition being relatively non-volatile, that is, sufiicientlynon-volatile, that they do not evaporate along with the dispersingagent, are left suspended in the air in very minute particles, known asan aerosol form. The mutual solvent, if one be used, may be eitherrelatively non-volatile or quite volatile, as it is immaterial whetherit remain in the atmosphere as an aerosol or vapor. Theconditioner-material must, however, be relatively non-volatile, as itfunctions to modify the size of the aerosol particles of insecticide andto give them added insect-penetrating properties.

Suitable insecticides for the purposes of the invention comprise suchmaterials as pyrethrum, rotenone-bearing plant extracts, and nicotine,with or without a synergist, such as sesame oil. These may be combinedwith germicides, such as carbolic acid, resorcinol, hexylresorcinol,propylene glycol, phenol, and thymol. Suitable dispersing agentscomprise liquefied gases such as dichlorodifiuoromethane, methylchloride, carbon dioxide, nitrous oxide, dimethyl ether, and varioushydrocarbons, with a mutual solvent for the insecticide and germicidewhen required. Such materials as ethanol, acetone, diacetone alcohol,methyl ethyl ketone, and methyl hexyl ketone, are suitable mutualsolvents. When desirable, carrier or conditioner-materials, such asolive oil, deodorized kerosene, refined cottonseed oil, or otherrelatively non-volatile materials, are added.

The proportions used in compounding the various ingredients are notcritical, except that the relatively non-volatile ingredients should notbe in quantity sufllcient to prevent the rapid evaporation of thedispersing agent. If the dispersing agent does not evaporate rapidly,the resulting spray is merely a wet spray with slow evaporation of thedispersing agent, resulting in rapid settling of the spray droplets,and, after the dispersing agent has evaporated, the remaining particlesof relatively non-volatile ingredients are large. Although thepermissible range of relatively non-volatile ingredients is not sharplyde-" fined, these ingredients should be so proportioned relative to thedispersing agent that when the composition is sprayed into air undernormal conditions of temperature and pressure, the dispersing agent willevaporate rapidly in the droplets, leaving. the active ingredientssuspended in aerosol form. Usually the relatively non-volatileingredients should not be substantially in excess of 20 percent of thecomposition.

The particular insecticide and germicide used must be compatible witheach other, that is, they must not be such as to destroy their lethalactionby their mutual presence. They must also be compatible with theother ingredients, and must be relatively non-volatile.

The following examples are illustrative of specific compositions inpreferable forms:

cent pyrethrum extract (20 percent pyrethrins), from about 2 percent to18 percent propylene glycol, and from about 10 percent to 30 percentethanol, dissolved in liquid 'dichlorodifluoromethane (total relativelynon-volatile ingredients not substantially in excess of 20 percent), isreadily dispersed and leaves the active ingredients in aerosol form,with very good lethal effect on both insects and bacteria in the air,reducing.

the number of bacteria in a treated space by from about 90 percent to 96percent.

Example 11 assspsc Having thus described the invention, what is claimedis:

1. A composition containing a relatively nonvolatile insecticide andolive oil for modifying the size oi aersol particles of the insecticideand to give them added insect-penetrating properties, said insecticideand olive oil being dissolved in a compressed liquid-dispersing agentwhich is gaseous under conditions or normal pressure and temperature,the proportions of ingredients being such that, when the composition issprayed in the air. the dispersing agent quickly evaporates, leaving theinsecticide suspended in aerosol form.

9. A composition containing from about 2 percent to 18 percent pyrethrumextract and -from about 2 percent to 18 percent propylene glycol, andamutual solvent, dissolved in liquid dichlorodifluoromethane, thepercentage of relatively non-volatile ingredients not beingsubstantially described, reducing the number of bacteria in a go inexcess of 20 ercent.

treated space by from about 90 percent to 99 percent.

Both compositions 01' Examples I and II are non-toxic to man and animaland are noncombustible.

EDWARD R. MCGOVRAN. LYLE D. GOODHUE.

